Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1994. / Includes bibliographical references (leaves 106-108). / by Jean-Marc P. Genkin. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997. / Includes bibliographical references (leaves 62-66). / by Marnie L. Harker. / M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2011. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 204-211). / This thesis relates to the emerging field of high-throughput density functional theory (DFT) computation for materials design and optimization. Although highthroughput DFT is a promising new method for materials discovery, its practical implementation can be difficult. This thesis describes in detail a software infrastructure used to perform over 80,000 DFT computations. Accurately calculating total energies of diverse chemistries is an ongoing effort in the electronic structure community. We describe a method of mixing total energy calculations from different energy functionals (e.g., GGA and GGA+U) so that highthroughput calculations can be more accurately applied over a wide chemical space. Having described methods to perform accurate and rapid DFT calculations, we move next to applications. A first application relates to finding sorbents for Hg gas removal for Integrated Gas Combined Cycle (IGCC) power plants. We demonstrate that rapid computations of amalgamation and oxidation energies can identify the most promising metal sorbents from a candidate list. In the future, more extensive candidate lists might be tested. A second application relates to the design and understanding of Li ion battery cathodes. We compute some properties of about 15,000 virtual cathode materials to identify a new cathode chemistry, Li₉V₃(P₂O₇)₃(PO₄)₂ . This mixed diphosphate-phosphate material was recently synthesized by both our research group and by an outside group. We perform an in-depth computational study of Li₉V₃(P₂O₇)₃(PO₄)₂ and suggest Mo doping as an avenue for its improvement. A major concern for Li ion battery cathodes is safety with respect to 02 release. By examining our large data set of computations on cathode materials, we show that i) safety roughly decreases with increasing voltage and ii) for a given redox couple, polyanion groups reduce safety. These results suggest important limitations for researchers designing high-voltage cathodes. Finally, this thesis describes the beginnings of a highly collaborative 'Materials Genome' web resource to share our calculated results with the general materials community. Through the Materials Genome, we expect that the work presented in this thesis will not only contribute to the applications discussed herein, but help make high-throughput computations accessible to the broader materials community. / by Anubhav Jain. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2012. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 111-116). / A three-dimensional dynamic model of the recently introduced semi-solid flow battery system is developed and applied to address issues with important design and operation implications. Because of the high viscosity of semi-solid flow battery suspensions, alternative modes of operation not typically used in conventional redox flow battery systems must be explored to reduce pumping energy losses. Modeling results are presented and compared to experimental observations to address important considerations for both stoichiometric and intermittent flow operation. The importance of active material selection, and its impact on efficient stoichiometric flow operation is discussed. Electrochemically active zone considerations relevant to intermittent flow operation of semi-solid flow batteries (or other potential electronically conductive flow battery systems) are addressed. Finally, the use of the model as a design tool for optimizing flow channel design to improve system level performance is demonstrated. / by Victor Eric Brunini. / Ph.D.

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Cataloged from student-submitted PDF version of thesis. / Includes bibliographical references (p. 161-182). / Polymers and colloids are important building blocks of life as well as many modern technologies. Driven by ow, polymers and colloids can express very complex yet interesting behavior. This thesis aims at a fundamental understanding of the dynamical properties of dierent polymer-colloid mixtures in flows using computer simulations. A special motivation comes from the blood clotting process. Our blood is a complex uid made of polymeric proteins and colloid-like cells. Controlled by ow, a blood-clotting protein (the so-called von Willebrand factor or vWF) can change shapes from a compact structure to an extended morphology. This polymeric protein later on forms composites with the colloidal cells (platelets) and completes the initial blood-clotting task. In this thesis, we build minimalist simulation models trying to capture the essential physics behind blood clotting. We first examine the behavior of single polymers in passive owing colloidal suspensions. Our results show that the presence of colloids has a pronounced eect on the unfolding and refolding cycles of collapsed polymers (which is believed to be a good model for vWF), but has negligible effects for non-collapsed polymers. Further inspection of the conformations reveals that the strong ow around the colloids and the direct physical compression exerted on the collapsed polymers diffusing in between colloidal shear bands largely facilitate the initiation and unraveling of the collapsed chains. We believe these results are important for rheological studies of (bio)polymer- (bio)colloid mixtures, and give insight on the activation of von Willebrand factor in owing cell suspensions. We then study interacting polymer-colloid mixtures in flows. In blood clotting, the formation of plug, which is essentially a polymer-colloid (vWF-platelet) composite, is believed to be driven by shear ow, and contrary to our intuition, its assembly is enhanced under stronger flow conditions. Here, inspired by blood clotting, we show that polymer-colloid composite assembly in shear flow is a universal process that can be tailored to obtain dierent types of aggregates including loose and dense aggregates, as well as hydrodynamically induced log-type aggregates. The process is highly controllable and reversible, depending mostly on the shear rate and the strength of the polymer-colloid binding potential. Our results have important implications for the polymer-colloid binding potential. Our results have important implications for the assembly of polymer-colloid composites, an important challenge of immense technological relevance. Furthermore, flow-driven reversible composite formation represents a new paradigm in non-equilibrium self-assembly. We also study binary colloidal mixtures and self-associating polymers, both of which are very relevant to blood clotting. Platelet margination refers to the phenomenon that for flowing red blood cell and platelet mixtures in vessels, the platelets will migrate to vessel walls. Using a simple binary colloidal suspension model, we show that the nonhomogeneous red blood cell distribution as well as the shear dependent hydrodynamic interaction is key for platelet margination. We believe this separation process is important not only in the biophysics of blood clotting, but also in applied science such as drug delivery or coatings. Catch-bonds refer to the counterintuitive notion that the average bond lifetime has a maximum at a nonzero applied force. They have been found in several ligand-receptor pairs including vWF/platelet GP1b-alpha. Here we use coarse-grained simulations and kinetic theory to demonstrate that a multimeric protein, with self-associating domain pairs, can display catch-bond behavior in ow. Our biomimetic design shows how one could build and tune macromolecules that exhibit catch-bond characteristics. We finally include an appendix that describes an unrelated project that is to solve for the block copolymer propagator in polymer field theory using Lattice Boltzmann method originally developed for hydrodynamics. Comparing to the conventional pseudo-spectral method, the Lattice Boltzmann approach is slightly inaccurate yet has many extra benefits including the optimal parallel computing eciency and the ability for grid refinements and arbitrary boundary conditions. / by Hsieh Chen. / Sc.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997. / Includes bibliographical references (leaves 89-91). / by Michael J. Whitney. / M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2012. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Cataloged from student-submitted PDF version of thesis. / Includes bibliographical references (p. 133-141). / 360° transverse domain walls (360DWs), which form readily from transverse 180° domain walls (180DWs) of opposite sense, demonstrate qualitatively distinct behaviors from their constituent 180DWs and are therefore of interest both from a physics perspective and for their applications in future domain wall devices. This thesis presents experimental and modeling-based investigation of the properties and behaviors of 360DWs including formation, magnetostatic behaviors, and response to field, AC, and DC driving forces. The formation of 360DWs is first examined by simulation in a model nanowire. An injection system capable of producing 360DWs from a wire and an injection pad is presented and its behavior is analyzed both by simulation and experimentally through magnetic force microscopy and scanning electron microscopy with polarization analysis. Next, a model multilayer system is used to demonstrate the magnetostatic behavior of 360DWs, demonstrating a much reduced stray field compared to 180DWs and a strong interlayer pinning behavior that allows the 360DW to act as a programmable pinning site. The richness of this magnetostatic behavior is analyzed experimentally in a rhombic ring system which readily generates 360DWs during reversal. The action of 360DWs is shown to dominate the reversal process, reducing switching fields and showing multiple reversal pathways with a strong dependence on field history. Simulations are used to explore the response of the 360DW to field and DC and AC currents. This highlights 360DW behaviors quite distinct from those of 180DWs, including the inability to be positioned by an applied field and the ability to be destroyed in place. 360DWs are shown to have an intrinsic resonant behavior in the GHz range, the exact frequency of which is broadly tunable by an applied field. Resonance can be excited by an applied AC current, and in conjunction with DC can be used to pin and gate 360DW propagation at a geometric pinning site, using globally applied currents and without impact on nonpinned domain walls. / by Mark D. Mascaro. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1987. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaves 178-188. / by Seok-Yeol Yoon. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1995. / Includes bibliographical references (leaves 116-120). / William B. Stockton. / Ph.D.

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1994. / Includes bibliographical references (leaves 222-239). / by Lu-Chang Qin. / Sc.D.